Historically, conscience objections have been linked only with anti-abortion causes, writes Lisa Harris, a professor of obstetrics and gynecology at the University of Michigan Health System, in the Sept. 13 issue of NEJM. The assumption, she writes, is that refusing to provide abortions is the "moral" thing to do, an understanding that leaves out abortion providers, many of whom provide the service because of strong moral beliefs, Harris said.

"Conscience doesn't mean you have a specific set of beliefs," Harris told LiveScience. "Conscience means you're a human being, and human beings vary in their beliefs."

The first conscience objection came shortly after the Supreme Court decision in Roe v. Wade. The 1973 Church amendment ensures that health-care workers cannot be required to perform abortions or sterilizations, nor can they be discriminated against for refusing.

More recently, conscience or refusal clauses have been under debate for pharmacists who do not want to supply emergency contraception, a form of hormonal birth control that can be taken up to 72 hours after unprotected intercourse. Many states, including Colorado, Florida and Maine, have laws allowing physicians and other medical professionals to refuse to dispense contraceptives if they have religious or moral objections. [The History & Future of Birth Control]

On the other hand, laws restricting abortion access don't come with conscience clauses, Harris said. For example, in May, Georgia's governor signed into law legislation that prevents most abortions after 20 weeks of pregnancy. That law leaves no "conscience clause" for providers who might see providing a patient with a later abortion as the moral choice in some cases, Harris said.

Many abortion providers are pro-abortion rights because they have strong moral beliefs regarding women's reproductive autonomy, because they are concerned with the mother's health or for other reasons, she said. These moral judgments get lost in the abortion debate, Harris said.

Harris said she'd like to see a clause recognizing moral reasons for having and providing abortions. "Right now, the only folks who are actively claiming moral ground are the people who oppose abortions," she said.

Compounding the problem, Harris said, is that there is no standard of care for enacting a conscience clause. Doctors are not required to meet any particular standard to do so, nor are there broad policies in place to ensure that patients are treated humanely in the process, she said.

"I've seen patients be really hurt and humiliated by doctors who they turned to, to help them get an abortion, who told them they were going to burn in hell and things like that," Harris said. She emphasized that she believes that conscience clauses are important and that no one should be forced to do something they morally object to, but added, "they have to do it humanely and safely, and right now we don't have any standard of care."

Outlining such standards would be a job for doctors, bioethicists and medical professional organizations, Harris said.

Stephanie Pappas is a contributing writer for Live Science. She covers the world of human and animal behavior, as well as paleontology and other science topics. Stephanie has a Bachelor of Arts in psychology from the University of South Carolina and a graduate certificate in science communication from the University of California, Santa Cruz. She has ducked under a glacier in Switzerland and poked hot lava with a stick in Hawaii. Stephanie hails from East Tennessee, the global center for salamander diversity. Follow Stephanie on Google+.